Rosetta mission: Philae lander 'wakes up' as planned

28 march 2014

The small robotic lander, which will be dropped onto comet 67P/Churyumov-Gerasimenko in November, was woken from its deep-space 'hibernation' today. This is a crucial milestone in the Rosetta mission, after wake-up of the orbiter in January. CNES is ready to receive the 1st science data from Philae.

300 scientists across Europe

After the Rosetta orbiter was woken up on 20 January, Philae - the compact 100-kg lander, attached for now to the main spacecraft - was reactivated and re-established contact with Earth on Friday 28 March. A 1st signal was received at 15h (Paris) by the Lander Control Centre (LCC) in Cologne, Germany.

In April, all onboard systems will be checked out to ensure that everything is working nominally. Solutions will be devised if anything goes wrong. CNES is closely involved in this 'post-hibernation checkout' phase. At the same time, the flight software that will control Philae during its descent and after landing will also be loaded.

Rosetta and the Philae lander (circled in red) will reach the comet in the early summer. Credits: CNES / ill. D. Ducros.

The challenge for Rosetta is to get close up to comet 67P/Churyumov-Gerasimenko, currently 650 million kilometres from Earth, and put its 10-instrument Philae lander on the comet surface. It will then escort the comet for more than a year as it approaches the Sun. Its aim: learn more about the inner structure of the comet's nucleus and characterize its nature and composition.

The Rosetta mission involves more than 300 scientists across Europe at four closely coordinated mission centres: the RMOC in Darmstadt (ESOC) for orbiter control operations; the RSGS in Madrid (ESAC) for orbiter science operations; the LCC in Cologne (DLR) for the Philae platform; and the SONC in Toulouse (CNES) for Philae science operations and navigation.

A real technological achievement

Philippe Gaudon and his team at the SONC, one of the four Rosetta mission centres, hosted at CNES's Toulouse Space Centre. Credit: CNES / E. Grimault.

As from today, the SONC (Science Operations and Navigation Centre) enters the post-hibernation operations phase. The mission centre is tasked with calculating safe landing trajectories for Philae, but that is not all. It will also plan and track science operations as well as process and archive the resulting data.

For the next three weeks, we will be inspecting the lander from every angle via telemetry link to ensure it is ready for the big day," says Philippe Gaudon, Rosetta project leader at CNES. "By the last week of April, preparation of onboard systems will be complete. After a training phase in May and June to ready the teams for landing operations, the main task over the summer will be to select the landing site."

About 20 people at CNES are involved in preparations for Philae's descent and touchdown. Wide-ranging expertise is needed to ensure the success of this remarkable feat of technology, with experts on hand in orbital mechanics to calculate Philae's descent trajectory, onboard systems to prepare for operations and data management to process and distribute the valuable information gathered on the comet.